Couplings are traditionally divided into two types, rigid couplings and flexible couplings With rigid couplings the torque transmission occurs directly without any possibility of flexing or the like. Flexible couplings on the other hand are constructed to compensate for certain wavelength prolongations and irregularities of the torque. Articulated joint couplings which receive longitudinal movements, parallel movements and angular deviations of the shafts are in this category of flexible couplings. This category also includes torsion spring couplings which can compensate for rotary oscillations or torsional vibrations and torque thrusts.